Metal silicide films may be processed by spraying and heating a metal silicide solution; by evaporation or sputtering technology, by chemical vapor disposition, or by thick film technology.
Thick film technology has been used in the electronics industry for more than 25 years. Thick film technology includes printing and firing a resistive paint in a desired pattern upon a suitable substrate. Resistive paints used in thick film technology typically include a conductive material, a glass frit, and a screening agent.
A base metal resistive paint is a resistive paint having no noble metals included in its composition.
Early thick film resistive paints varied primarily in the composition of the conductive materials. The glass frit, after melting, was used primarily as a bonding agent to bond the conductive material to the substrate. The chemical composition of the glass frit was selected in regard to its melting point which was required to be below the melting point of the conductive material used. The screening agent was selected for consistency and ease of printing. Commercially available glass frits and screening agents were typically used.
Chemical compounds found in a typical glass frit are inorganic, such as minerals. These chemicals typically exhibit a number of undesirable properties, such as: high TCR; widely variable thermal stability; poor short time overload characteristics; variable resistance values due to uneven mixing; and visible cracks and fissures.
Certain materials were typically mixed with metal silicide powder to obtain the wide range of resistivity and low TCR (temperature coefficient of resistance) desired.
British Pat. No. 1,559,523 disclosed a resistor composition selected from tungsten disilicide, molybdenum disilicide, vanadium disilicide, titanium disilicide, zircohium disilicide, chronium disilicide and tantalum disilicide and fired at 970.degree. C. to 1150.degree. C.
U.S. Pat. No. 2,891,914 disclosed a fired electrical resistor made from MoSi.sub.2 and a borosilicate glass frit.
U.S. Pat. No. 3,027,332 disclosed the use of silicides of Mo, Cr, V, Ti, Zr and Tr. Historically, silicide resistors were fired between 970.degree. to 1150.degree. C., and some as high as 1300.degree. C.
U.S. Pat. No. 3,498,832 disclosed a fired electrical resistor using Cr.sub.3 Si and TaSi.sub.2.
U.S. Pat. No. 3,661,595 discloses use of molybdenum silicide and tungsten silicide for use in making a fired electrical resistor.
U.S. Pat. No. 4,309,997 discloses a resistance material employing a metal silicide selected from MoSi.sub.2 ; WSi.sub.2 ; VSi.sub.2 ; TiSi.sub.2 ; ZrSi.sub.2, CrSi.sub.2 and TaSi.sub.2 fired at 970.degree. C. to 1150.degree. C.
A paper entitled "A Novel Conducting Glaze" by E. Dancy was published in Ceramic Bulletin, Volu,e 55, No. 6 in 1976, which mentioned using MoSi.sub.2 as a conductive material for use in thick film resistors.